1. Field of the Invention
The invention relates to a surge current protection circuit and motors using the same.
2. Description of the Related Art
Surge current protection circuits are widely used in power supplies of electronic devices such as motors, so as to prevent current higher than a rated value from damaging the electronic devices and power systems. As shown in FIG. 1, a conventional surge current protection circuit employs a negative temperature coefficient (NTC) thermistor. However, there are several problems with the NTC thermistor: since it continuously operates, it generates large calorific power and high temperature and consumes a lot of electricity, which reduces reliability of the electronic device.
Another typical surge current protection circuit is implemented by a mechanical relay contact parallel connected to a resistor. But the mechanical relay contact has short lifetime, which reduces reliability of the electronic device and increases production cost thereof.